I'm going a bit by memory, but the Westray provisions did a couple of things. As my colleague spoke about, it created the ability to prosecute corporations for either negligent criminal behaviour or criminal conduct that required subjective mens rea. It did impose a duty on employers who have a responsibility for the safety of their workers.
That isn't exactly what this bill does. This bill is about employers vis-à-vis those in their charge, effectively. It's not an exact parallel in that respect.